It's an issue, we have the same one too. Our drummer is a very good drummer technically, but hit's 'em hard, and struggles to hold back when asked. You can start with the best intentions, but once the adrenalin kicks in, it's hard to calm it down again. Also, the guitarist is more than happy to keep turning up as the gigs goes on, of course, which results in me clattering the strings hard to punch through. Actually, it's so loud, that normally it's the singer who ends up being lost in the mix, and he gets really fed up, to the point where he has now given notice to leave us.
It's all down to self control I'm afraid. You all have to sit down and discuss it, and once you're happy with the balance in a sound check, you must stick with that religiously, and resist the urge to get carried away. The drummer is very much the linchpin in that, and must play according to the circumstances. Any good musician should be able to do that.